Halacha for Sunday 13 Iyar 5781 April 25 2021

Tying Tzitzit Strings and Plastic Cable Ties on Shabbat

In the previous Halachot we have discussed some basic laws of tying and untying knots on Shabbat. The general rule is any knot that is either “professional,” i.e. requires some skill to make, or “permanent,” i.e. is meant to last for a prolonged amount of time, is forbidden to be made on Shabbat.

Tying an Additional Knot on Top of a Knot Which Existed Before the Onset of Shabbat
We have already mentioned that some authorities rule stringently and prohibit tying a double knot on Shabbat, for this is considered a professional knot. (For instance, when one ties one’s shoes, one usually makes one knot and another bow on top of that. Making another knot on top of the first one makes the knot stronger.)

Thus, the Poskim write that if there was one knot tied before Shabbat, one should not make an additional knot on top of it, for the second knot is the primary knot forbidden on Shabbat. This is similar to a situation where one letter was written before Shabbat and writes another letter on Shabbat thereby completing the word. For instance, if the letter “Alef” was already written and one then adds the letter “Bet” on Shabbat, it is considered that one has written the word “Av” (“father” in Hebrew), a word with a meaning, on Shabbat, which is a Torah prohibition. (It is a rabbinic prohibition to write even one letter on Shabbat.)

Similarly, if one adds another knot to a pre-existing knot on Shabbat, one transgresses the forbidden work of tying on Shabbat. Maran Rabbeinu Ovadia Yosef zt”l rules likewise in his Chazon Ovadia-Shabbat, Part 5, page 68. Although we have written previously that Maran zt”l rules that one who ties a double knot on Shabbat has on whom to rely, it is nevertheless worthy to act stringently regarding this matter.

Tightening Loosened Tzitzit
If one’s Tzitzit loosened on Shabbat, one may not tighten it on Shabbat, for this resembles tying a double not. This is especially true since there is room to say that tying Tzitzit is a kind of “professional” knot and Tzitzit are considered tied “permanently” since one never intends to untie them.

Plastic Cable Ties
The modern-day Poskim discuss whether or not one may use plastic cable ties on Shabbat. Should their use pose a concern of the forbidden works of tying or building on Shabbat? Maran zt”l rules (ibid. page 75) that there is no prohibition involved and one may use them on Shabbat, for this is not considered a “knot”; rather, the plastic cable is only caught and tightened. The Torah never discussed such a reality and our Sages never banned this kind of action, for this does not resemble the forbidden work of tying at all.

Summary: One may not tighten loosened Tzitzit strings on Shabbat. One may use plastic cable ties on Shabbat.

Ask the Rabbi


ספר אביר הרועים - בית מידות
ספר אביר הרועים
לפרטים לחץ כאן

הלכה יומית מפי הראש"ל הגאון רבי יצחק יוסף שליט"א

דין ברכת שפטרנו מעונשו של זה
לחץ כאן לצפייה בשיעורים נוספים

Recent Halachot

"תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא"

נדה ע"ג א'

8 Halachot Most Popular

Eating and Washing One’s Self Yom Kippur

Some Laws of Yom Kippur All are obligated to fast on Yom Kippur, including pregnant and nursing women. Any woman whose health is at risk due to the fast should consult a prominent Torah scholar who is well-versed in these laws and he should render his ruling whether or not she must fast. One whose ......

Read Halacha

Motza’ei Yom Kippur

Adding From the Mundane Onto the Holiness One must add some of the mundane weekday onto the holiness of Yom Kippur upon its exit, i.e. one should not end this holy day immediately with nightfall; rather, one should wait another few minutes. Thus, it is prohibited to eat or perform work on Motza&rsq......

Read Halacha

The Obligation to Eat in the Sukkah

Since there is not so much time left to discuss the laws of Sukkot, let us now spend the next few Halachot discussing some pertinent Halachot for the upcoming Sukkot holiday. A Meal of an Established Character Throughout the entire Sukkot holiday, both during the night and day, it is prohibited ......

Read Halacha

Reciting Selichot Alone, Without a Minyan

Question: If one is unable to recite Selichot with a Minyan (quorum of at least ten Jewish men) for whatever reason or if a woman wishes to recite Selichot and she cannot do so with a Minyan, may one recite the Selichot texts alone or should one abstain from doing so? Answer: If one wishes to rec......

Read Halacha


The Laws of Eating a Kezayit of Bread in the Sukkah on the First Night of Sukkot and One who is Uncomfortable in the Sukkah

In the previous Halacha we have discussed that one may not eat an established meal outside of the Sukkah anytime during the Sukkot holiday. One must be aware that the reward for the Mitzvah of Sukkah is that it protects one during turbulent times (see Zohar, Parashat Tetzaveh). The Mitzvah of......

Read Halacha

The Custom of “Tashlich”

Following Mincha services of the first day of Rosh Hashanah, it is customary to go to a seashore, river, well, or pit in order to recite the order of “Tashlich.” If there is no river, lake, or pond in close proximity of one’s vicinity, it is likewise perfectly acceptable to recite ......

Read Halacha

The Proper Behavior for the Days of Rosh Hashanah-The Custom of Maran zt”l

It is customary to eat red meat and sweet foods on the days of Rosh Hashanah, as the verse in Nechemia states, “Go eat fatty foods and drink sweet beverages and sent gifts of food to those who do not have, for the day is sanctified to our Lord.” One may not fast at all on Rosh Hashana......

Read Halacha

Blowing the Shofar on Rosh Hashanah

It is a positive Torah commandment to hear the Shofar blasts on the day of Rosh Hashanah, as the verse states, “It shall be a day of [Shofar] blasts for you.” One may not speak between the various sets of Shofar blasts and certainly not during the blasts themselves. The Poskim disagree r......

Read Halacha